PUDDLING HARROW FOR PRECISE PADDY PREPARATION USING HORIZONTAL BALANCE CONTROL

摘要

Sowing and transplanting on the irrigated paddy field have been achieved after the land preparation, so leveling operation has been considered to be very important not only for water management but for better effect of chemical herbicide and fertilizer, higher seed germination ratio and standing ratio of young rice plant. The accuracy of rotary and leveling operation for later operations, such as transplanting chemical application and so on, was not considerable problem on small sized plots about 0.3-0.4ha. As the rearrangement of arable land has been promoted, however, securing the leveling accuracy has been technical assignment to improve the germination ratio, the number of standing rice plants, and the agrochemical effects. The objective of the research was the development of a puddling harrow for irrigated paddy field that could perform land preparation and precise leveling by keeping the rear-attached machine horizontal all the time. Field tests were conducted for leveling performance. The summaries of the research were as followings. 1. Ride-on type of a puddling harrow was fabricated so that the paddling plate of the harrow could be controlled. The control ranges were from -6° to 6° for depth control, from -22° to 80° for the tilting angle of a plank, from 2.0m to 3.5m for the leveling width. 2. Response time was 0.6 ± 20% seconds, and the delay time was so small that it seemed not to interfere the operation. 3. Field efficiency was improved 1.5 times compared with the conventional type. The maximum level difference, standard deviation, and the portion within ± 2.5cm were increased by 25%, 9.5%, and 0.9%, respectively. Improvement in early rice growth ratio and weed-removal effect was expected. 4. The estimated cost was 83,3000 won/ha for a prototype and 110,000 won/ha for a conventional machine, respectively. It indicated that we could save the annual cost by 25%.